We know that Thor's hammer has a weight, and that the weight is irrelevant to the ability to wield Mjolnir - but rather how worthy the wielder is.
However, most of the people who have canonically wielded Mjolnir have been quite strong - Captain America, Beta Ray Bill - even a regular human paramedics would have some strength as part of the job. For example, if an replica of Mjolnir were made of regular steel, Captain America would easily be able to wield the estimated 30-50kg hammer.
However, has there been a situation where someone was deemed "worthy" to wield the hammer, but would not have normally had the strength an equivalent non-enchanted hammer, but was still able to lift it? For example, Thor is immobilised, a small child of pure heart is nearby and is able to lift the hammer to free him?
Similarly, if one is worthy of wielding Mjolnir, do they gain the equivalent strength to lift anything of comparable weight or just the hammer?
Edit for clarification:
If we assume Mjolnir when stripped of all enchantments has a fixed weight, and that weight for arguments sake is 100kg, it would stand to reason that the only people capable of wielding it would be super strong. This question is about how the enchantments alter how wieldable it is. Lets assume a small child was deemed worth by Odin of wielding Mjolnir, but this child can lift at most 20kg. The enchantment is useless, as even though the child may wield Mjolnir, it effectively cannot because its not strong enough to lift the unenchanted weight.